Step 1
Get your set of impact sockets out and find one that will fit nicely onto your locking wheel nut. It should be a very close fit; the socket should be just a touch too small to fit onto it properly.
Step 2
Take a rubber hammer and pound the socket onto the nut. Almost all nuts are made of a much softer alloy than hardened impact sockets, so the nut will deform to the socket before the socket will deform to the nut. There should be no damage to your socket. The nut will still be able to be reused; it just won't be "locking" anymore. If you are using normal sockets that are not hardened, impacted sockets, slight socket damage may occur.
Step 3
Use an impact gun in reverse. Using an impact gun works well because the impacts will keep the socket securely attached to the nut. If you do not have an impact gun, use a normal ratchet. You may need to attach a breaker bar to it in order to gain enough leverage.
ChicksFan, August 2010